This invention relates to percutaneous transluminal coronary angioplasty (PTCA), and more particularly, to an inflation device for inflating a balloon of a PTCA catheter, the inflation device having means for monitoring inflation data and transmitting such data to a receiver and display device. The invention also relates to a monitor and communication system by which inflation data of an inflation device are monitored and transmitted to a remote receiver for recording and display of information concerning those data.
Coronary angioplasty is an accepted medical procedure for dilatating a stenosis which partially blocks an artery. The procedure is carried out by advancing a balloon carried by a dilatation catheter until the balloon is across the stenosis. The balloon is inflated, usually to a pressure of several atmospheres, to dilatate the stenosis and open the artery. The balloon is then deflated and retracted from the arterial system. Typically, the balloon is constructed of a high-strength polymeric material which assumes a prescribed diameter when inflated by a prescribed pressure. Hence, the dilatation process is carefully controlled by the balloon selected for the procedure as well as the pressure applied to the balloon.
It is necessary, during the procedure, that the balloon be advanced and retracted in the arterial system. This is accomplished by advancing the balloon in a deflated state, inflating it when it is positioned across the stenosis, and thereafter deflating the balloon to retract it from the arterial system. Thus, the balloon is inflated in situ when it is positioned across the stenosis.
In order to assure proper inflation of the dilatation balloon, it is important that the cardiologist knows the inflation pressure applied to the balloon. The balloon, when inflated, effectively blocks the artery. Therefore, it is also important that the duration of the inflation is known to the cardiologist. Since the angioplasty procedure ordinarily requires several inflations of the balloon at the location of the stenosis, it is also desirable that the cardiologist know the number of inflations which have been conducted.
Heretofore, inflation devices included pressure gauges attached to the inflation device in fluid communication with the lumen of the balloon catheter. The pressure gauge on the inflation device displayed the pressure within the lumen, and hence, within the dilatation balloon, the pressure usually being displayed in atmospheric pressure. Examples of balloon inflation devices having pressure gauges may be found in U.S. Pat. No. 5,019,041 granted May 28, 1991 to Robinson et al. and U.S. Pat. No. D-309,663 granted Jul. 31, 1990 to Robinson. Using such inflation devices, the cardiologist would determine the pressure of the inflation by observing the pressure gauge, would determine the duration of inflations by observing elapsed time on the cardiologist's watch or on a clock in the operating room, and would observe the number of inflations by mentally keeping track of them.
The memory of the persons present during the procedure, as well as any procedural logs maintained by them, served as the only record of the pressures, durations, and numbers of inflations performed during the angioplasty procedure. Memories, and human recorded logs, were not always accurate. Thus, even during the procedure, the cardiologist could lose track of the number of inflations, the duration of any particular inflation, or even be distracted from observing the pressure gauge during the inflation procedure.
The inflation device was often awkward to operate, particularly due to the positioning of the pressure gauge on the inflation device housing. Since the cardiologist is also concerned with operating other equipment during the procedure, such as positioning the guide catheter, balloon catheter and/or any guidewire, manipulating the inflation device housing so that the pressure gauge could be observed was an added annoyance to the cardiologist.
As a result of some of these concerns, attempts have been made to electronically monitor the inflation pressures through the use of a sensor mounted to the inflation device, with a separate display device for displaying the inflation pressure and duration. Examples of these devices are found in Wallace U.S. Pat. Nos. 5,004,472 and 5,021,046, Wallace et al U.S. Pat. No. 5,009,662 and Foote et al. PCT Publication No. WO 90/11040. However, these prior devices physically connected the display device to the inflation device by electronic cables which interfere with the manipulation of the inflation device, so the awkwardness of manipulating the inflation device was not completely alleviated.
The inflation device should be sterile. Under most circumstances, the inflation device is manufactured and supplied to the cardiologist in a sterile condition and is simply discarded after each procedure. However, the electronic cable connections between the electronic sensor and the monitor device are costly, representing a significant replacement expense if the cables are also discarded. While the cables and sensor devices could be sterilized, that approach is also quite costly. A less desirable alternative is simply not to replace or sterilize the cables, but that alternative is not acceptable to most cardiologists.